Surgical cutting tool

Abstract

Surgical cutting tool for manufacturing of a recess in a firm body tissue, in particular in a bone and/or in a cartilage, with a milling range rotatable around a central axis of rotation, with an outside lateral surface and an internal area substantially defined by the lateral surface and turned away from the worked on body tissue. The lateral surface is formed with at least two machining cutting edges, which proceed at the lateral surface from a machining center to a machining edge of the milling range and which are in particular spiral curved. Apertures are arranged adjacent to the cutting edges for the transport of the cutting splinters into the internal area, whereby the cutting edges are interrupted by means of recesses in such a way that the cutting edges are formed by individually cutting elements.

The invention claimed is: 
     
       1. A surgical cutting tool for forming a recess in a body tissue, comprising:
 a milling area on the surgical cutting tool that is rotatable around a central axis of rotation and has an outside lateral surface and an internal area which is substantially defined by the outside lateral surface and facing away from the machined body tissue, the outside lateral surface having at least two curved machining cutting edges which are formed thereon to provide a milling head and which proceed at the outside lateral surface from a machining center to a machining edge of the milling area, and 
 apertures formed in the surgical cutting tool arranged adjacent to the cutting edges and configured to transport cutting splinters from the machined body tissue into the internal area, 
 whereby the cutting edges are interrupted by recesses formed in the cutting edges to form individual cutting elements, 
 wherein the outside lateral surfaces between two cutting edges comprise at least two stop surfaces which are arranged substantially parallel and adjacent to the cutting edges, and the stop surfaces are configured to limit the penetration of the cutting edges into the body tissue in relation to the penetration depth into the tissue, and 
 wherein a first stop surface of the at least two stop surfaces limiting a first penetration of the cutting edge into the tissue has a first differential height in relation to a tip of the cutting edge, wherein the first differential height is essentially constant or slightly declining between a region of the rotational center and a circumferential region of the surgical cutting tool, 
 and a second stop surface of the at least two stop surfaces extends to the opening of the second cutting edge and limits the penetration following the first penetration of the cutting edge into the tissue, wherein the second stop surface has a second differential height in relation to the tip of the cutting edge, which second differential height decreases from the region of the rotational center toward the circumferential region. 
 
     
     
       2. The surgical cutting tool of  claim 1 , comprising a helical groove formed on the outside lateral surface, wherein the helical groove breaks through the cutting edges at the lateral surface in the area of the recessions of the cutting edges in such a way that the groove forms a substantially aligned continuation of the recessions within the cutting edges and a chip breaking partition of the cutting edges into cutting elements is formed, whereas the lengths of the cutting elements decrease from the machining center to the machining edge. 
     
     
       3. The surgical cutting tool of  claim 2 , wherein the cross section of the groove is rounded or angular. 
     
     
       4. The surgical cutting tool of  claim 1 , wherein the apertures are formed essentially parallel to the cutting edges and continuously open and end in the area of the rotational center and in the area of the circumferential edge. 
     
     
       5. The surgical cutting tool of  claim 1 , wherein each of the cutting edges subtends, when observed in cross section, a cutting angle alpha, which is formed between the lateral surface and a cutting surface which is facing away from the workpiece, the cutting angle alpha increasing from the cutting edge at the area of the rotational center towards the cutting edge within the area of the circumferential edge. 
     
     
       6. The surgical cutting tool of  claim 5 , wherein the milling area is made of a Cr—Co alloy. 
     
     
       7. The surgical cutting tool of  claim 1 , wherein the cutting edges provide, when observed in cross section, a clearance angle gamma, which is formed between the lateral surface and a cutting surface facing the workpiece, and which clearance angle decreases from the cutting edge within the area of the rotational center toward the cutting edge within the area of the circumferential edge. 
     
     
       8. The surgical cutting tool of  claim 7 , wherein the clearance angle gamma decreases continuously in relation to the distance from the rotational center. 
     
     
       9. The surgical cutting tool of  claim 1 , wherein the stop surfaces have a concave cross section. 
     
     
       10. The surgical cutting tool of  claim 1 , wherein the cutting edge which is facing the workpiece is essentially constant over the entire cutting edge. 
     
     
       11. The surgical cutting tool of  claim 1 , wherein the cutting edge is separated by recesses into approximately 5 to 8 cutting elements. 
     
     
       12. The surgical cutting tool of  claim 1 , wherein the milling area is hemispherical or formed like an triangle or flat or conically or mushroom-shaped. 
     
     
       13. The surgical cutting tool of  claim 1 , wherein the milling area has recesses in the side of the lateral surface that are configured to permit access to difficult accessible areas of the body tissue and an envelope of the milling area remains essentially unchanged compared to a full working tool. 
     
     
       14. The surgical cutting tool of  claim 1 , wherein the milling area comprises about 2 to 8 cutting edges which are arranged equidistantly over the lateral surface. 
     
     
       15. The surgical cutting tool of  claim 1 , wherein the milling area is made of a high-temperature resistant metal. 
     
     
       16. The surgical cutting tool of  claim 1 , wherein the milling area comprises 6 cutting edges arranged equidistantly over the lateral surface.